巻号一覧
後続誌
50 巻, 12 号
選択された号の論文の6件中1～6を表示しています
- |<
- <
- 1
- >
- >|
研究論文
-
��田 千里, ��川 克之, 坂本 敏正, 森 隆資, 高田 寿1978 年 50 巻 12 号 p. 715-720
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーThe effects of sulfur on solidification structures and mechanical properties of Fe-C-Si alloys having lamellar graphite were investigated by the observation and measurement of graphite structure, tensile strength, electrical resistance and damping capacity. The band structure, which was formed vertically against the direction of solidification, was prevented completely by controlling temperature of the furnace precisely. The lamellar graphite spacing increased by increasing the sulfur content, but it decreased conversely over 0.05%. The tensile strength was not influenced remarkably by sulfur content within the limits of this experiment. A characteristic regular pattern was observed on the surface of lamellar graphite, but the regular pattern became irregular by the addition of sulfur. This seemed to be closely related to the adsorption of sulfur on the basal plane of graphite. The effect of graphite spacing or sulfur content on the electrical resistance was very small. The damping capacity decreased slightly at 0.03%S, and it increased remarkably by increasing the sulfur content. This phenomenon was similar to the relation between the graphite spacing and sulfur content.抄録全体を表示PDF形式でダウンロード (795K) -
雄谷 重夫, 中野 耕作, 江崎 裕, 鞘師 守1978 年 50 巻 12 号 p. 721-726
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーQuantitative metallography and EPMA analysis were made on Cu-8%Sn alloy containing Ce quenched at various stages of directional-free and unidirectional solidification. Also a dilute Cu-0.03%Sn alloy containing Ce was solidified unidirectionally to determine the effective distribution coefficient. Inverse segregation of Sn is moderated in the alloy containing Ce. The fact is attributed to i) increase in the effective distribution coefficient of Sn and moderated microsegregation, ii) coarser dendritic structures and coalesence of dendrite arms preventing the remaining solute-rich liquid to flow outward, and iii) grain refining obstructing the fluid flow.抄録全体を表示PDF形式でダウンロード (855K) -
小松 康彦, 杉本 繁利, 北川 久善, 谷村 凞1978 年 50 巻 12 号 p. 727-732
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーThe study aims to compare the characteristics of high temperature oxidation in various low alloyed spheroidal graphite cast irons in order to improve the material for recent exhaust manifolds which require stronger heat resistance. Six kinds of material were investigated. They were heated up in the temperature range of 600∼950°C for 100hrs, then the weight gain due to oxidation, the thickness of oxide layer and the amount of metallic oxides were measured. Hence the amount of metallic oxides which was eliminated by means of shot blast treatment seems to be a more accurate value of metallic oxidation than the conventional weight gain. This value can be considered to be equal in meaning to the weight of oxygen consumed for metal oxidation.
As a result of adding various alloy elements (1% respectively) to the cast iron which contained 3.6%C and 2.8%Si, anti-oxidation property is improved in the order of Si>Cr>Al. However, it is hardly improved by Ni. The reason why Si contributes to the improvement of anti-oxidation are considered to be that Si content increases in the oxide layer and Fe2SiO4 forms as a result. By contrast, neither Cr or Al oxides, FeO·Cr2O3 and FeO·(Fe,Al)2O3, can be recognized appreciablly, because of the small amount in the oxide layer. Although two specimens, one adding 2%Si and the other adding 1%Cr and 1%Al, show good anti-oxidation property in this study, the high silicon cast iron is concluded to be the optimum material, since castability and machinability are better than the others.抄録全体を表示PDF形式でダウンロード (719K) -
高柳 猛1978 年 50 巻 12 号 p. 733-738
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーNumerous fine cracks occur in the silica hydrogel obtained by the addition of NH4Cl into colloidal silica in proportion to the progress of natural drying. The apparent density of the silica gel made by NH4Cl addition after sufficient drying in desiccator is 0.9g/cm3. The value is lower than 1.3g/cm3 of the gel obtained by drying of original colloidal silica under the same condition described above. Accordingly, the dried gel made by NH4Cl addition is extremely porous and brittle. The dried gel made by NH4Cl addition contains a small amount of absorbed water, NaCl produced by reaction between NH4Cl and colloidal silica, and NH4Cl crystals which precipitated as a result of excess addition in the colloidal silica.
Characteristic changes of this dried gel when heated are as follows. Most of the absorbed water evaporates starting from 50°C through to 130°C, but part of the absorbed water gradually evaporates up to the high temperature range. The NH4Cl in the dried gel starts to decompose from 120°C and is entirely volatilized by the temperature reaches 350°C. The NaCl in the dried gel begins to sublimate around 500°C and sublimation increases in proportion to the temperature rise. The majority of Na+ is entrapped in the dried gel at this stage and accelerates the crystallization of the dried gel. For example, the silica gel made by 20cc of 10%NH4Cl solution added to 100cc colloidal silica-S starts crystallization into β-cristobalite at 854°C and crystallization is rapidly accelerated by the temperature rise. However, some of the silica gel remains without crystallizing. This remaining silica gel crystallizes into a high temperature type of tridymite at the temperature of 947°C and mixed among the β-cristobalite.抄録全体を表示PDF形式でダウンロード (780K) -
蘇 国璋, 大出 卓, 大平 五郎1978 年 50 巻 12 号 p. 739-744
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーThe fluidity of near eutectic molten iron of flake and spheroidal graphite cast irons was studied by keeping the pouring temperature, carbon equivalent, clay content in sand mold and ramming operation the same. The total length of molten iron which flowed into the three thin plate gutters in a sand mold was measured. The moisture content in the mold was one of the most important factors of the fluidity of casting. The influence of moisture content on the fluidity of flake graphite cast iron was greater than spheroidal graphite cast iron. The fluidity of the castings increased with the decrease of superheating in both irons. Crystallization of primary crystals in molten iron decreased fluidity. Molten iron with eutectic composition had the best fluidity. The stoppage of the molten iron flow was explained by the characteristic shape of the solidified iron tips.抄録全体を表示PDF形式でダウンロード (854K) -
田中 雄一, 井川 克也1978 年 50 巻 12 号 p. 745-750
発行日: 1978/12/25
公開日: 2012/06/02
ジャーナル フリーThe influence of matrix structure on the fracture toughness of spheroidal graphite cast irons was studied by means of crack opening displacement (COD) test. When compared at the same 0.2% offset yield strength, the iron with ferrite-pearlite fine duplex matrix structure had higher critical crack tip COD value (δc) than the irons with spheroidal pearlite or lamellar pearlite structure. The crack initiation temperature at δc=0.04mm became lower as the volume fraction of ferrite in the duplex matrix increased.抄録全体を表示PDF形式でダウンロード (763K)
- |<
- <
- 1
- >
- >|